title: Vectorcardiographic monitoring of patients with acute myocardial infarction and chronic bundle branch block.
abstract: OBJECTIVE
  This study was set up to describe vectorcardiographic patterns in patients with bundle-branch block and acute myocardial infarction.
  
  
  RESULTS
  Sixty-five patients admitted to the coronary care unit with bundle-branch block and suspected acute myocardial infarction were monitored by dynamic vectorcardiography with trend analysis. In 28 patients, a clinical diagnosis of acute myocardial infarction was made. In patients with left bundle-branch block and acute myocardial infarction, the pattern of QRS vector-difference evolution was similar to that in patients with the narrow QRS complex, while ST vector-magnitude changes increased over time. Using a cut-off value for QRS vector-difference at 12 h of more than 20 microVs and a specific trend curve pattern, acute myocardial infarction in the presence of left bundle-branch block could be diagnosed with an accuracy of 71%. For patients with right bundle branch block, using a maximum ST vector-magnitude of > 200 microV during the first 4 h, acute myocardial infarction could be diagnosed with a 78% accuracy.
  
  
  CONCLUSIONS
  Our results indicate that dynamic vectorcardiography is a valuable tool in diagnosing and monitoring acute myocardial infarction in patients with bundle branch block.
authors.affiliation: Department of Medicine, Ostra University Hospital, Göteborg, Sweden.
authors.forename: P
authors.initials: P
authors.lastname: Eriksson
authors.forename: K
authors.initials: K
authors.lastname: Andersen
authors.forename: K
authors.initials: K
authors.lastname: Swedberg
authors.forename: M
authors.initials: M
authors.lastname: Dellborg
mesh_terms: D000368:Aged; D002037:Bundle-Branch Block / Q000150:complications / Q000175:diagnosis* / Q000503:physiopathology; D005260:Female; D006329:Heart Conduction System; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000150:complications / Q000175:diagnosis* / Q000503:physiopathology; D011237:Predictive Value of Tests; D012680:Sensitivity and Specificity; D014672:Vectorcardiography